Fiberoptic connector and methods

ABSTRACT

A fiberoptic connector is constructed entirely of metal and includes structure to radiate heat. Preferably, the fiberoptic connector also includes an arrangement to indicate whether the fiberoptic connector is holding an energized optical fiber. Preferably, the heat radiating structure includes fin structure and a metal stamping projecting from the connector housing. The indicating arrangement preferably is a temperature sensitive strip secured to the housing, which changes color based upon the heat radiated by the optical fiber carried within. Methods of indicating an energized fiberoptic connector and of dissipating heat from a fiberoptic connector are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/881,260, filed Jun. 30, 2004; which is a continuation of U.S.application Ser. No. 09/967,491, filed Sep. 28, 2001, now U.S. Pat. No.6,758,601; which applications are incorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to fiberoptic connectors. In particular, thisdisclosure concerns fiberoptic connector constructions and methods thatmay be used across of range of powers, e.g., 500 milliwatts to 2 watts.

BACKGROUND

In fiberoptic communications, there are situations when it is desired tosend a signal over a long distance, for example, from the east coast tothe west coast of the United States. In such situations, repeaterstations are utilized every 500 miles or so. The repeater stations readthe signal and repeat the signal. Repeater stations are needed becausethe power being transmitted along the fiber is not great enough to beable to sustain and transmit the signal over the very long distance ofseveral thousands of miles.

The use of repeater stations is expensive. Thus, it is desired tominimize the number of repeater stations that are needed. One way ofminimizing the number of repeater stations needed is by transmittinghigh powers through each optical fiber. In previously used systems,powers along the range of up to about 400 milliwatts are utilized.

Higher powers transmitted through optical fibers are more dangerous thanlower powers. Improvements in fiber optic connectors are desired toensure safety for operators and equipment when transmitting powersgreater than 400 milliwatts.

SUMMARY

In one aspect, this disclosure describes a fiberoptic connector suitablefor use across a range of powers, for example, in the range of 500milliwatts and up, such as up to 2 watts. In general, one embodiment ofa fiberoptic connector is disclosed as including a connector housingdefining an interior volume sized to hold an optical fiber and anopening in communication with the interior volume. An optical fiber isoriented within the interior volume of the connector housing. Atemperature indicator is secured to the connector housing.

In one embodiment, the connector housing includes a plurality of finsprojecting from the housing wall, and the connector housing comprisesmetal. In a preferred embodiment, there is a cover pivotally connectedto the connector housing. Preferably, this cover comprises metal.Preferably, in some embodiments, there is a stamping secured to andprojecting from the connector housing. Preferably, this stampingcomprises metal.

In another aspect, a method for indicating an energized fiber opticconnector is disclosed. The method includes a step of providing afiberoptic connector including a housing holding an optical fibertherewithin, sensing a temperature of the fiberoptic connector, andproviding a signal when the temperature of the fiberoptic connectorcrosses a threshold.

In another aspect, this disclosure describes a method of dissipatingheat from a fiberoptic connector. The method includes a step ofproviding a fiberoptic connector including a metal housing holding anenergized optical fiber, wherein the housing includes a plurality offins and a metal stamping secured to and projecting from the housing.Heat generated by the energized optical fiber is radiated through themetal housing, the plurality of fins, and the metal stamping.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of a fiberoptic connectorhousing and cable assembly constructed according to principles of thisdisclosure;

FIG. 2 is a perspective view of only the fiberoptic connector housingassembly of FIG. 1;

FIG. 3 is an exploded, top, front perspective view of the fiberopticconnector housing assembly of FIGS. 1 and 2;

FIG. 4 is an exploded, top, rear perspective view of the fiberopticconnector housing assembly of FIGS. 1 and 2;

FIG. 5 is a cross-sectional view of the fiberoptic connector housingassembly of FIGS. 2-4; the cross-section being taken along the line 5-5of FIG. 2;

FIG. 6 is a cross-sectional view of the fiberoptic connector housing andcable assembly of FIG. 1; the cross-section being taken along the line6-6 of FIG. 1;

FIG. 7 is a cross-sectional view of the fiberoptic connector housing andcable assembly of FIG. 1 similar to FIG. 6, but showing a cover on thehousing in an open position; and

FIG. 8 is a cross-sectional view of the fiberoptic connector housing andcable assembly of FIGS. 1, 6, and 7 secured within an adapter to asecond fiberoptic connector and cable assembly.

DETAILED DESCRIPTION A. Some Problems with Existing Arrangements.

Existing fiberoptic connectors are often made from injection moldedplastic. When such injection molded constructions carry high intensityfibers, the energy emitted from the optical fiber causes the injectionmolded housing to increase in temperature. Such increases in temperaturecan sometimes cause the injection molded housing to melt. Of course,such melting can damage equipment and can lead to fires.

Some existing connectors are made from metal. It has been found,however, that such metal connectors, when carrying high intensityfibers, do not adequately dissipate heat transmitted to them from thefibers. Because the heat is not dissipated, these all metalconstructions can start fires.

Further problems with existing fiberoptic connectors include the factthat there is no way of easily knowing whether the fiberoptic cablewithin the connector is energized. In past arrangements, the personinspecting would sometimes view the end of the optical fiber todetermine whether it was transmitting power. In such situations, if theoptical fiber is carrying high intensity power, this type of visualinspection can cause damage to the person's eye.

B. The Embodiment of FIGS. 1-8.

One embodiment of a fiberoptic connector is shown generally in the FIGS.at 10. In general, the fiberoptic connector 10 is preferably constructedto address the problems of the existing arrangements discussed above. Inparticular, in preferred embodiments, the fiberoptic connector 10includes an indicating arrangement 12 to communicate to a person that anoptical fiber being carried by the connector 10 is energized. Further,in many preferred embodiments, the fiberoptic connector 10 includes heatradiating structure 14 that is constructed and arranged to dissipateheat generated by an energized optical fiber carried by the connector10. In preferred embodiments, the fiberoptic connector 10 is constructedentirely of metal, such that it will not melt from the heat generated bythe optical fiber.

In reference now to FIG. 1, a fiberoptic connector housing and cableassembly is shown in general at 16. In the embodiment illustrated, theassembly 16 includes the fiberoptic connector 10 and a fiber optic cable18. A strain-relief boot 19 is shown in FIGS. 1, 6, and 7 protecting thecable 18 from sharp bends.

The fiberoptic connector 10 includes a housing 20 that holds an opticalfiber 22 (FIGS. 6 and 7) therewithin. Also visible in the particularembodiment illustrated in FIG. 1 is a door or cover 24 connected to theconnector housing 20, as well as a stamping 26 secured to and projectingfrom the connector housing 20.

The connector housing 20 includes a surrounding wall 28 that defines aninterior volume 30 (FIG. 5) that is sized to hold the optical fiber 22.The wall 28 also defines a front opening 32 (FIGS. 3 and 7), which is incommunication with the interior volume 30. The wall 28 also defines arear opening 34 (FIGS. 4 and 5), which allows the optical cable 18 toexit from the housing 20.

Attention is directed to FIGS. 3 and 4, which show exploded views of thefiberoptic connector 10. The housing 20 includes a front end 36 thatdefines the opening 32. A terminal end of the optical fiber 22 extendsthrough the opening 32. The wall 28 includes a longitudinal connectorguide 38 in the form of a pair of longitudinally extending slots 40, 41on opposite sides 42, 43 of the housing 20. Preferably, the slots 40, 41are parallel to a longitudinal axis 44 that runs along the housing 20.The slots 40, 41 are also preferably spaced from a bottom or base 46 ofthe housing 20. In preferred embodiments, the slots 40, 41 arepositioned to receive guide rails in an adapter, such as the adapterdescribed in U.S. Pat. No. 6,142,676 to Lu, and assigned to ADCTelecommunications, Inc. of Minnetonka, Minn., the assignee of thispatent. U.S. Pat. No. 6,142,676 and its parent, U.S. Pat. No. 5,883,995,are incorporated by reference herein. An example of an adapter is shownin FIG. 8 at 180. The adapter 180 in FIG. 8 is connecting the assembly16 to a second fiberoptic connector and cable assembly 190.

The cover 24 is pivotally secured to the connector housing 20 to pivotabout an axis 48, which is orthogonal to the longitudinal axis 44 andspaced rearwardly of the front face 36. FIGS. 1, 5, and 6 show the cover24 in a closed position, while FIG. 7 shows the cover 24 pivoted to anopen position that exposes the opening 32.

The cover 24 includes a cam pin receiving slot 50 positioned to receivea pin 182 integral with adapter 180, as described in U.S. Pat. No.6,142,676, when the cover 24 is in the closed position as the connector10 is inserted into the adapter 180. The pin 182 rotates the cover 24into the open position. As described in U.S. Pat. No. 6,142,676, removalof the connector 10 from the adapter 180 reverses the action, so thatthe pin 182 causes the cover 24 to pivot to the closed position. Themanner in which the fiberoptic connector 10 interacts with the adapter180 described in U.S. Pat. No. 6,142,676 is known and is as described inU.S. Pat. No. 6,142,676.

The housing 20 defines a pair of curved seats 54, 55 on opposite sides42, 43, respectively, of the housing 20. The curved seats 54, 55 supportand hold the cover 24 in place. Further, the curved seats 54, 55 allowthe cover 24 to pivot and move smoothly between its open and closedpositions. The cover 24 includes a pair of hinge mounts 58, 59, eachhaving a curved surface 60, 61, (FIG. 4) respectively, that is sized tosmoothly engage seats 54, 55 to allow the cover 24 to pivot. Extendingbetween the hinge mounts 58, 59 is a rod 62. Adjacent to the rod 62 is aslot, in particular, an aperture 64 extending through the cover 24. Aswill be described further below, a portion of the stamping 26 interactswith the cover 24, in particular the rod 62 and aperture 64, to helphold the cover 24 in place relative to the housing 20. In preferredembodiments, the cover 24 is secured to the housing 20 in fastener-freeconstruction. By “fastener-free construction”, it is meant that thereare no screws, rivets, pins, bolts or other types of fastenersphysically connecting the cover 24 to the housing 20.

The housing wall 28 defines an opening 70 through a top portion 72 ofthe wall 28. The opening 70 helps to dissipate and emit heat from theinternal volume 30 of the connector 10. Along the top portion 72, thereincludes structure 74 to help secure the stamping 26 to the housing 20.In particular, the structure 74 includes a pin 76 projecting upwardlyfrom the top portion 72 of the wall 28. Adjacent to the pin 76 is afirst and a second bar 78, 79. Each of the bars 78, 79 is adjacent to arespective side 42, 43. As will be described below, the stamping 26includes a heel 82 that mateably engages the structure 74 to help holdthe stamping 26 relative to the housing 20. Between the rear end 37 andthe top portion 72 defining the mounting structure 74 is a cylindricalbody 84 of the housing 20. Extending from and projecting from the body84 is a plurality of cooling fin structure 86. In general, the finstructure 86 helps to dissipate heat from the optical cable 18 byradiating it therefrom. In the particular embodiment illustrated in theFIGS., the fin structure 86 includes at least a first fin 88 and asecond fin 89. As can be seen in FIG. 4, in preferred embodiments, thefins 88, 89 generally have the shape of a truncated circle, each havinga projecting tail 90, 91 having straight, parallel edges 93, 94. In theparticular embodiment illustrated, the first and second fins 88, 89 arespaced apart from each other to define a receiving gap 92 therebetween.As will be explained below, the receiving gap 92 communicates with aportion of the stamping 26.

In preferred embodiments, the housing 20 is constructed entirely ofmetal. In this manner, the housing 20 will not melt from the heatgenerated by the fiber optic cable 18, even when powers up to 2 wattsare transmitted therethrough.

Still in reference to FIGS. 3 and 4, the cover 24 includes a face 100,which operates to block the opening 32, when the cover 24 is in itsclosed position relative to the housing 20. The face 100 is generallyorthogonal to a base 102. The base 102 defines the aperture 64, asdescribed above. Further, in this particular embodiment, the face 100defines a window 104 that holds and exposes the indicating arrangement12. The indicating arrangement 12 will be described further below.Preferably, the cover 24 is constructed entirely of metal.

Still in reference to FIGS. 3 and 4, the stamping 26 is now furtherdescribed. Preferably, the stamping 26 is secured to and projects fromthe connector housing 20. In preferred embodiments, the stamping 26extends along at least 50 percent, and more preferably, 75-90 percent ofthe length of the connector housing 20 parallel to the longitudinal axis44. In preferred embodiments, the stamping 26 includes a flange 110cantilevered from the housing 20. Preferably, the flange 110 includesthe heel 82 attached to the housing 20. On opposite sides of the heel 82are a free end 112 and a lid 114. An end wall 116 defines the free end112. The end wall 116 defines a curved opening or slot 118. When theflange 110 is assembled and secured to the housing 20, the slot 118 isin communication with and received by the receiving gap 92 between thefirst and second fins 88, 89. This engagement between the cooling fins88, 89 and the flange 110 helps to further dissipate and radiate heat.

A ramp surface 120 is angled relative to the end wall 116. In preferredembodiments, the ramp surface 120 is angled acutely, preferably about45-85 degrees relative to the end wall 116. An extension 122 extendsfrom the ramp surface 120 to a fork 124. The fork 124 extends betweenthe extension 122 and the heel 82. In the preferred embodimentillustrated, the fork 124 is angled relative to the extension 122, at anobtuse angle. In the one shown, the angle is shown to be 95-140 degrees.As can be seen in FIG. 3, the fork 124 includes first and second tongs126, 128 with the heel 82 being oriented therebetween.

In preferred embodiments, the heel 82 is a planar structure 129 having apair of straight, parallel sides 131, 132. The planar structure 129defines a hole or aperture 134.

To assemble the flange 110 onto the housing 20, the sides 131, 132 areplaced between and against the bars 78, 79 of the mounting structure 74.The aperture 134 receives the pin 76. Preferably, the flange 110 is thenstaked to the housing 20 at the intersection of the aperture 134 and thepin 76.

Projecting from the heel 82 is the lid 114. When the flange 110 issecured to the housing 20, the lid 114 extends over a portion of thecover 24. In particular, the lid 114 defines a tip 136 that extends overthe rod 62. When the cover 24 is pivoted into an open position, the endof tip 136 is received within the slot or aperture 64, and preferablypenetrates the aperture 64. When the cover 24 is in the closed position,the lid 114 presses on and engages the rod 62 to help hold the cover 24in place relative to the housing 20.

In preferred embodiments, the flange 110 further includes a plurality oftabs 138, 139 extending from and projecting from the extension 122. Ascan be seen in FIGS. 3 and 5, the tabs 138, 139 are bent from theextension 122 at an angle. In the particular embodiment illustrated, theangle is an acute angle, such as between 10-80 degrees. The tabs 138,139 help to further radiate heat from the fiberoptic connector 10.

The tabs 138, 139 also help to secure the connector 10 to the adapter180, as shown in FIG. 8.

As mentioned previously, the fiberoptic connector 10 preferably includesindicating arrangement 12 that provides a signal when the temperature ofthe fiberoptic connector 10 crosses a trigger point, or threshold. Inother words, when the fiberoptic connector 10 is carrying an energizedoptical fiber 22, the optical fiber 22 will radiate heat, that willraise the temperature of the connector housing 20. The indicatingarrangement 12 will provide a signal by sensing the temperature toindicate that the connector 10 is carrying an energized optical fiber22. Further, when the optical fiber 22 is not energized, the indicatingarrangement 12 will sense the lower temperature of the housing 20 andwill provide a signal that the optical fiber 22 is not energized, and isthus safe to visually inspect.

In preferred embodiments, the indicating arrangement 12 provides avisual signal. The visual signal could be in the form of lights,indicia, digital or analog readouts, to cite of few examples of thosepossible. In the preferred embodiment, the visual signal is a colorchange. In particular, the indicating arrangement 12 includes atemperature sensitive strip 150 that is affixed to any portion of theconnector housing 20. The strip 150 can be secured to any portion of thehousing 20, since the housing 20 is constructed of metal and willradiate heat from all portions. In the particular embodimentillustrated, the strip 150 is shown as being secured to the window 104of the cover 24. The temperature sensitive strip 150 is constructed andarranged to change color when a temperature of the connector housing 20reaches a threshold level.

For example, when the optical fiber 22 is not energized, the strip 150will be a first color, such as black. After the optical fiber 22 isenergized, the optical fiber 22 will emit heat. This heat will be sensedby the strip 150, which will cause a change in color of the strip 150,once the temperature exceeds a certain amount. For example, once thetemperature exceeds 180° F., the strip 150 will change from the firstcolor (such as black) to a second color (such as red or blue or white).This will provide a signal to the user that the optical fiber 22 isenergized, and the user should not open the cover 24 to visually inspectthe fiber 22. Once the optical fiber 22 is not energized and is notcarrying power, the temperature of the housing 20 will drop, and thetemperature sensitive strip 150 will sense this. The temperaturesensitive strip 150 will change from its second color back to its firstcolor, after passing the trigger point.

The temperature sensitive strip 150 can be made from temperaturesensitive liquid crystal sheets. This is available from Edmond Optics,101 E. Glouchester Pike, Barrington, N.J. 08007.

In reference now to FIGS. 6 and 7, the internal structure of thefiberoptic connector 10 can be seen. In particular, the fiberopticconnector 10 includes optical fiber 22 surrounded by an optical ferrule160. A jacket 162 covers the optical fiber 22 from where the ferrule 160ends. A hub 164 holds the ferrule 160. Spring 166 can be seen urging thehub 164 toward the front face 36 of the connector 10. A further outerprotective layer (not shown) and an inner strength member, for example,Kevlar (not shown), are provided around cable 18, for protecting jacket162 and for crimping to a rear housing portion 163 of housing 20 with acrimp ring 165.

In use, a method for indicating an energized fiberoptic connector mayinclude providing a fiberoptic connector, such as the connector 10 shownin FIGS. 1-8, including housing 20 holding the optical fiber 22therewithin. A temperature of the fiberoptic connector 10 is sensed, anda signal is provided when the temperature of the fiberoptic connector 10crosses a threshold.

Preferably, the step of providing the fiberoptic connector 10 includesproviding housing 20 having at least a portion of a first color, and thestep of providing a visual signal includes changing the portion of thefirst color to a second color when the temperature of the fiberopticconnector 10 crosses a trigger point.

In preferred embodiments, the step of providing the fiberoptic connector10 includes providing the housing 20 having the temperature sensitivestrip 150 secured thereto, wherein the temperature sensitive strip 150has the first color. Preferably, the step of changing the portion of thefirst color includes changing the first color of the temperaturesensitive strip 150 to the second color when the temperature of thefiberoptic connector 10 crosses a trigger point.

In preferred embodiments, the step of providing a fiberoptic connector10 includes providing a housing 20 having the openable and closeablecover 24 connected thereto. Preferably, the temperature sensitive strip150 is secured to the cover 24.

In use, a method of dissipating heat from a fiberoptic connectorincludes providing a fiberoptic connector, such as the connector 10described above. The connector 10 preferably includes metal housing 20operably holding energized optical fiber 22. The housing 20 includes theplurality of fins 86. Further, there is preferably the metal stamping 26secured to and projecting from the housing 20. The method preferablyincludes radiating heat generated by the energized optical fiber 22through the metal housing 20, the plurality of fins 86 and the metalstamping 26.

It is intended that the specification and illustrated embodiments beconsidered as exemplary only. Many embodiments of the invention can bemade.

1. A fiber optic cable assembly, comprising: a) a fiber optic cableincluding an optical fiber; b) a connector attached to an end of thefiber optic cable, the optical fiber of the fiber optic cable extendinginto an interior volume of the connector; c) a temperature indicatorcarried by the fiber optic assembly, the temperature indicator providinga visual signal of when the optical fiber of the fiber optic cable isenergized.
 2. The assembly of claim 1, wherein the visual signalprovided by the temperature indicator occurs when the temperature of theconnector reaches a threshold level, the temperature of the connectorreaching the threshold level due to heat generated by the optical fiberwhen the optical fiber is energized.
 3. The assembly of claim 2, whereinthe threshold level includes temperatures exceeding 180° F.
 4. Theassembly of claim 1, wherein the temperature indicator changes colorwhen the optical fiber of the fiber optic cable is energized.
 5. Theassembly of claim 1, wherein the temperature indicator is a temperaturesensitive strip affixed to the connector.
 6. The assembly of claim 1,further including a cover that connects to the connector, the coverbeing arranged to cover a front opening in the connector through whichthe optical fiber of the fiber optic cable can be visually inspected. 7.The assembly of claim 6, wherein the cover is pivotally connected to theconnector.
 8. The assembly of claim 6, wherein the temperature indicatoris a temperature sensitive strip affixed to the pivoting cover.
 9. Theassembly of claim 6, wherein the cover defines a window, the temperatureindicator being located within the window of the cover.
 10. The assemblyof claim 9, wherein the temperature indicator is a temperature sensitivestrip located within the window of the pivoting cover.
 11. The assemblyof claim 10, wherein the temperature sensitive strip changes color whenthe optical fiber of the fiber optic cable is energized.
 12. Theassembly of claim 11, wherein the temperature sensitive strip changesfrom a first color to a second color when the connector reaches athreshold level, the first color being black.
 13. The assembly of claim12, wherein the second color is one of red, blue, and white.
 14. Theassembly of claim 1, further including a heat radiating structure thatdissipates heat generated by the optical fiber when the optical fiber isenergized.
 15. The assembly of claim 14, wherein the heat radiatingstructure is attached to the connector.
 16. The assembly of claim 14,wherein the heat radiating structure including fins that project fromthe connector to dissipate heat generated by the optical fiber when theoptical fiber is energized.
 17. The assembly of claim 14, wherein theheat radiating structure includes a metal stamping projecting from theconnector that dissipates heat generated by the optical fiber when theoptical fiber is energized.
 18. The assembly of claim 1, furtherincluding a cover pivotally connected to the connector, the cover beingarranged to cover a front opening in the connector through which theoptical fiber of the fiber optic cable can be visually inspected, and ametal stamping projecting from the connector that dissipates heatgenerated by the optical fiber when the optical fiber is energized. 19.The assembly of claim 18, further including fins that project from theconnector to dissipate heat generated by the optical fiber when theoptical fiber is energized.
 20. The assembly of claim 18, wherein theconnector and the cover are each constructed of metal.
 21. The assemblyof claim 1, wherein the optical fiber is operably energized to carry 2watts of power.